'-=»  -l&l 


Xs\ 


U.  S.  DEPARTMENT   OF  AGRICULTURE, 

BUREAU   OF   ENTOMOLOGY— CIRCULAR  No.  121. 

L.  O.  HOWARD,  Knlomologist  and  Chief  of  Bureau. 


THE  OYSTER-SHELL  SCALE  AND 
Till]  SCURFY  SCALE. 


A.  L.  Quaintance,  in  GJiarge  of  Deciduous  Fruit 
Insect  Investigations, 

AM) 

E.  K.  Sasscer,  S<  n  ntific  Assistant. 


36826     Cir.  121—10 1 


WASHINGTON    :  GOVERNMENT  PHINTING  OFFICE   :   1910 


B  UREA  U  OF  ENTOMOLOGY. 

L.  O.  Howard,  Entomologist  and  Chief  of  Bureau . 

C.  L.  Marlatt,  Assistant  Entomologist  and  Acting  Chief  in  Absence  of  Chief. 

R.  S.  Clifton,  Executive  Assistant. 

('has.  J.  Gilliss,  Chief  Clerk. 

F.  H.  Chittenden,  in  charge  of  truck  crop  and  stored  product  insect  investigations. 

A.  D.  Hopkins,  in  charge  of  forest  insect  investigations. 

W.  D.  Hunter,  in  charge  of  southern  field  cm  p  insect  investigations. 

F.  M.  Webster,  in  charge  of  cereal  and  forage  insect  investigations. 

A.  L.  Quaintance,  in  charge  of  deciduous  fruit  insect  investigations. 

E.  F.  Phillips,  in  charge  of  bee  cultun  . 

D.  M.  Rogers,  in  charge  of  preventing  spread  of  moths,  field  work. 
Rolla  P.  Currik,  in  charge  of  editorial  work. 

Mabel  Colcord,  librarian. 

Deciduous  Fruit  Insect  Investigations. 

A.  L.  Quaintance,  in  charge. 

Fred.  Johnson,  S.  W.  Foster,  E.  L.  Jenne,  P.  R.  Jones,  A.  G.  Hammar,  R.  W. 
I'raucher,  C.  W.  Hooker,  J.  R.  Horton,  E.  J.  Hoddy,  W.  Postiff,  agents  and 
experts. 

E.  \Y.  Scott,  C.  II    Gable,  J.  F.  Zimmer,  entomological  assistants. 

[Cir.  121] 

(") 


Circular  No.  121.  Issued  April 30, 1910. 

United  States  Department  of  Agriculture, 

BUREAU   OF   ENTOMOLOGY. 
L.  O.   HOWARD,   Entomologist  and  Chief  of  Bureau. 


THE  OYSTER-SHELL  SCALE  AND  THE  SCURFY  SCALE. 

idosaphes  ulmi  L.  and  Ckionaspis/ur/ura  Fitch.) 
By 
A    L.  Qi  iiNTANi  i  ,  In  i  ha    ■  ■         ous  Fruit  Insect  1      sligations, 

and 
E.  R    Sassceh    -  i       lant. 

INTRODUCTION. 

The  oyster-shel]  scale  (Lepidosaphes  ulmi  L.)  and  the  scurfy  scale 
(Chionaspis  furfura  Fitch)  are,  with  the  exception  of  the  San  Jose 
or  Chinese  scale  (Aspidiotus  pernidosus  Comst.),  more  frequently  the 
subject  of  inquiry  by  orchardists  than  all  other  species  of  scale  insects 
combined.  These  two  scale  pests  are  now  very  generally  distributed 
throughout  the  country,  and  from  their  relatively  conspicuous  appear- 
ance are  often  detected  by  observant  fruit  growers  who  frequently 

believe  them  to  he  the  more  serious  San  dose  scale.      The  ovst  er-shell 

and  scurfy  scales,  while  not  dangerous  in  the  sense  of  generally  causing 
the  death  of  infested  trees,  are,  however,  of  considerable  economic 
importance.  The  complete  killing  of  individual  branches  of  apple 
trees  by  either  species  is  a  matter  of  frequent  observation,  and  trees 
so  badly  infested  are  frequently  greatly  stunted  and  retarded  in  their 
growth,  resulting  perhaps  in  extreme  cases  in  the  death  of  t  he  trees. 
Of  the  two  species  considered,  the  oyster-shell  scale  has  been  and  is 
at  the  present  time  the  more  important.  Its  injuries  to  certain 
shade  trees,  especially  poplar  and  maple,  have  been  the  cause  of  much 
complain t  during  recent  years.  Such  shade  trees  are  ordinarily  not 
3prayed  for  scale  insects,  and  the  increase  of  these  pests  from  year  to 
year  is  thus  checked  only  l>\  their  natural  enemies.  The  writers 
bave  frequently  seen  maple  and  poplar  trees  literally  incrusted  from 
top  t"  bottom  witli  the  oyster-shel]  scale,  manj  "I'  the  limbs  killed, 
and  in  rarer  instances  the  trees  quite  dead — -without  doubt  owing  to 
the  at t ack  of  i  his  scale  insect. 

[Clr.  121] 

(1) 


THE  OYSTER-SHELL  SCALE. 

(Lepidosaphes  ulmi  L.) 

ORIGIN    AND   DISTRIBUTION. 

The  origin  of  the  oyster-shell  scale  is  a  matter  of  some  uncertainty. 
It  has  a  world-wide  distribution,  and  was  introduced  into  the  New 
England  colonies  at  an  early  date.  The  first  American  account  of  this 
pest  was  written  by  Enoch  Perley  in  1794,  in  which  he  stated  that  it 
was  doing  considerable  damage  to  the  apple  in  Cumberland  County, 
Maine.  In  the  early  sixties  it  had  reached  the  Mississippi  River,  and 
at  the  present  writing  (April,  1910)  occurs  in  every  State  of  the  Union 
with  the  possible  exception  of  South  Dakota,  Oklahoma,  and  Texas. 
Its  occurrence  in  these  States  is  practically  certain,  but  there  appear 
to  be  no  records  in  literature  to  this  effect,  and  it  has  not  been  received 
from  these  States  by  the  Bureau  of  Entomology.  The  insect  is  very 
t mublesome  in  the  Northern  States  and  is  especially  common  in  the 
New  England  States  and  those  bordering  the  Great  Lakes. 

DESCRIPTION    AND   LIFE    HISTORY. 

This  insect  has  received  the  common  name  "oyster-shell  scale," 
owing  to  the  resemblance  of  its  scale  or  covering  to  a  long,  narrow 
oyster  shell,  as  may  be  seen  by  reference  to  figure  1.  The  adult 
female  scales  are  about  one-eighth  of  an  inch  in  length,  usually  brown 
to  dark  brown  in  color,  though  occasionally  they  have  a  grayish 
appearance  which  is  due  to  bleaching  over  winter.  If  present  in 
large  numbers,  for  want  of  room  they  assume  various  more  or  less 
curved  shapes.  The  scale  of  the  male  in  shape  and  color  resembles 
that  of  the  female,  but  is  smaller  and  possesses  at  the  posterior 
extremity  a  small  hinge  or  flap  which  permits  the  exit  of  the  adult 
male. 

If  during  winter  or  early  spring  one  of  the  female  scales  be  removed, 
numerous  small,  oval,  white  eggs  varying  in  number  from  40  to  100 
will  be  revealed,  and  at  the  anterior  portion  can  be  seen  the  dead  and 
shriveled  body  of  the  female. 

In  Canada  and  the  Northern  States  there  is  thought  to  be  but  one 
full  brood  annually,  whereas  in  the  Middle  and  Southern  States  the 
species  is  double  brooded. 

The  following  records  from  literature  and  from  the  Bureau  of  Ento- 
mology will  indicate  the  time  in  the  spring  of  hatching  of  the  eggs  of 
this  insect,  in  various  localities.  This  time  will,  of  course,  vary  with 
the  season,  but,  in  general,  as  long  ago  stated  by  Doctor  Mygatt,  in 
Illinois,  will  for  any  locality  be  shortly  after  the  time  of  the  falling 
of  the  blossoms  of  the  apple. 

[Clr.  121] 


Ontario:   I         batch  aboul  firsl  week  of  June  (Jarvie 

)  l        hatch  latter  part  of  Maj  to  early  June  (Fell  . 

Hampshirt     I        batch  in  late  May  to  early  June  (Sandei 
Vermont:  Eggs  hatch  in  late  June  (Ste^ 

batch  aboul   middle  of  June  or  later,  depending  upon  the 
(Hitchings). 

I      pi    imena  received  June  lv.  1909,  from  Stittsville,  Mich.,  nearly  all 
bad  batched  (Sasscer  i. 


Fig.  1.— Theoyster  shell  -rale  (Lepidosapka  ulmi).    All  enlarged.    (Original.) 

In  specimens   received   May  24,  1909,  from  Lamoille,  Minn.,  eggs  were 
hatching  in  numbers  when  received  (S 

Indiana:  [n  specimens  received  from  Elwood,  May  It.  L909,  eggs  were  hatching  in 
numbers  when  received    3 

batch  in  laic  May  to  early  June  i  <  iossard). 
Second-bro  were  found  under  many  scales  Augusl  22,  and  a  few  young  crawl- 

ing at  < !le\ eland  (Quainl  in  i 

I  In  specimens  received  A]>ril  30,   L908,  from  Parkersburg,  W.  Va., 

iwling  in  numbers    - 
fClr.  121 1 


Missouri  (Wrighl  County):  Eggs  hatch  early  in  May.  Insect  double  brooded 
according  to  a  Mr.  Wright  (Riley). 

Olden,  Mo.,  eggs  hatched  March  29,  1907;  apple  trees  bloomed  March  24  (Girault). 

Ozark  region,  Missouri,  eggs  hatch  about  April  25  to  middle  of  May  (Taylor). 

Illinois  (Cook  County):  Eggs  hatch  about  June  6,  females  reach  full  growth  by 
August  1,  and  oviposit  August  12-28  (Riley). 

District  of  Columbia:  Eggs  hatch  May  5-14  (Quaintance). 

July  4,  eggs  already  deposited  by  most  females  and  young  crawling  (Quaintance). 

Maryland:  Eggs  hatch  early  in  May  (Symons). 

Eggs  of  first  brood  hatch  in  May;  eggs  of  second  brood  hatch  last  week  of  July  to 
first  week  of  August  (Johnson). 

College  Park,  many  recently  settled  scales  in  evidence  May  21  (S.  W.  Foster). 

Delaware:  Eggs  usually  hatch  in  early  May  (Houghton). 

New  Jersey:  Eggs  hatch  during  early  June  (Smith). 

Tennessee:  In  eastern  Tennessee  eggs  hatch  during  first  two  weeks  of  April  (Cham- 
bliss). 

Eggs  begin  to  hatch  in  April  and  those  of  the  second  brood  along  in  July  and  August 
(Bentley). 

This  information  as  to  the  period  of  hatching  of  eggs  in  various 
parts  of  the  country  is  of  importance  as  bearing  on  the  time  to  spray 
for  the  destruction  of  the  young  larvae. 

The  female  molts  twice  in  the  course  of  her  growth,  and  in  the 
adult  condition  is  entirely  without  legs  or  eyes,  being  nothing  more 
than  a  reproductive  sack  with  her  sucking  mouth  parts,  through 
which  the  food  is  taken,  inserted  in  the  tissues  of  the  plant.  The 
adult  male  differs  radically  from  the  female  in  that  it  is  provided 
with  antennae  and  one  pair  of  wings,  the  second  pair  being  present 
in  the  form  of  club-shaped  organs  known  as  balancers  or  halteres. 
During  the  process  of  metamorphosis  the  mouth  parts  entirely  dis- 
appear, and  a  second  pair  of  rudimentary  eyes  assumes  their  place. 
Being  without  any  means  of  taking  in  food  the  male  is  naturally 
very  short  lived,  its  only  mission  appearing  to  be  the  fertilization  of 
the  female. 

MEANS    OF   DISTRIBUTION. 

Transportation  by  nursery  stock,  scions,  or  by  grafting  or  budding 
material  is  perhaps  the  only  way  this  insect  is  carried  from  one  section 
of  the  country  to  another,  and  this  in  a  large  measure  accounts  for  its 
wide  distribution.  Locally  it  can  bo  transferred  from  plant  to  plant 
only  while  in  the  young  or  crawling  stage.  The  young  are  often  seen 
crawling  on  other  insects,  such  as  beetles,  or  upon  the  feet  of  birds, 
and  may  in  this  way  be  carried  some  distance.  Man  and  domestic 
animals  may  also  assist  in  their  dissemination,  and  it  is  possible  that 
the  winds  blow  them  from  plant  to  plant. 

FOOD    PLANTS. 

The  oyster-shell  scale  has  a  wide  range  of  food  plants,  but  is  com- 
monly found   on   apple,    maple,   horse-chestnut ,   poplar,   willow,   and 
[CIr.  ii'i  J 


lilac.     The  following  is  a  lisl  of  the  plants  on  which  it  is  known  to 
occur: 


Alder  (Alnus  rugosa  Spn 

Almond  i  Prunus  Bp.),  '  Ihina. 

Americaxi    aspen    (Populus    tremuloides 

Michx 
American   bladdernul   (Staphylea   • 

I. inn 
Amorpha  sp.,  exotic. 
Apple  I  Pyrus  malus  Linn.  I. 
Apple.  crab  i  Pyrus  sp    . 
Apricot    Prunus  ar    ■  nicu  a  I. inn.  . 

Arrow -w 1     I  l1!1 

Ash  i  !''■■'■  nui  am* ricana  Linn    .     F.  ex 

a  Isior  Linn.  i,  I  Fraxinua  Bpp    - 
Balm    of    Gilead    \  I'uiinlus    balsami/era 

Linn 
Basswood      Tilia   americana    I. inn.),    (T. 

angu.sti jol in,  from  Germany). 
Beech  ea  Sudw.). 

Bilberrj  i  VacciniummyrtillusIAan..). 
Birch,  white  (Betula  populi/olia  Ait.). 
Birch,  river  (Betula  nigra  Linn.). 
Bittersweel  I  (  <  lastrus  Bp 
Blackthorn  (Prunus  spinosa  Linn.). 
Box  (Bush*  semperviri  ns  Linn.). 
Boxelder  (Acer  negundo  Linn.). 
Broom  i '  ytisus  scoparius  Link,  i,  Gurnsey. 

(C.  nubigt  nus  Link,  i,  from  Gurnsej  i  " 
Buckeye  (JEsculus  glabra  Wild.  i. 
Buckthorn  •  9  cathartica  Linn 

Butternut  (Juglans  cinerea  Linn.). 

'  alhn, 11  Bp.,  Sweden. 

'  'mm  lUa  Bp. 

Camphor      tree      (Camphora      officinalis 

Steud.). 
( 'assia  Bp.,  in  greenb 
Cherry  1  Prunus  Bp 

<  beetnul    ( 'astanea  americana  Rai 

<  !•  mutts  paniculata  Thunb. 
t  'ocoa  palm  from  Barbad 

Bp. 

Cranberrj  1  Vaccinium  sp 
Currant;  black    Ribes  nigrum  Linn 
Currant,  red  '  Ribi  1  ruhru,:    I  1 
D  "1   Cornusalba Linn.  ,(C.albava.r. 

sibirim  Lodd        ?C.  alterna  Mars) 

■       \     Mej         '     sanguinca 
Linn.). 
Elm,  English     Ulmus  campestris  Smith). 
Elm,  purple-leaved  (I7Zmus  scabra,  var. 
purpurea  Koch 

>horbia  palustris  Linn..  Germany. 
[Clr.  lL'tl 


False     bittersweet     (Celastrus     scandens 

Linn 

arii  ■  Linn.). 
Filbert  1  ( 'orylus  sp.). 

folium  Linn.'). 

1 -el.,  n  .  aosbati  Linn.  , 

Goatsbeard  1  4t*uticus  Sylvester  Kost.  1. 
Grape  1  l  tfis  mni/era  Linn 
Backberrj  (Celtis  occidental^  Linn 
Bawthorn    Crataegus  crus-galli  Linn 

oxyacantha  Linn.  1. 
Helianthemum    chamxeistus    Mill.,    Eng- 
land. 
Ileniii  ;/,,-,,,,  ^|,.  .  England  and  Sweden. 
Beather  1  ( 'alluna  Bp.  1. 
Holly  i  //<  1  in  nata  Thunb.  1. 
Bone}  3uckle  1  /  onicera  sp.). 
Bop  tree  (Pfc  /,  1;  trifoliata  Linn.  . 
Boree-chestnut    1  JSsculus  hippocastanum 

Linn.). 
5or<  na  duleis  Thunb. 
June-berrj  1  .!///<  lanchii  r  spp.  1. 
Leather    leaf    (Chamxdaphne    calyculata 

Moench  1. 
Lilac  (Syringa  persica  Linn    .    S    vulgaris 

Linn 
Lime  (Citrus  Bp.). 
Linden.     1  n, ,   Basswood. 
Locust,  cultivated   <  Robinia    pseuda 

Linn.). 
Locust,  water  (Gleditsia  aquatica  Marsh). 

.Maple.       Btllped       I'.lr.T      pi  n  tis,/l <  u  met/ in 
Linn 

Maple,  sugar  I  leer  surrlmrinuiu  Linn.). 

Maple,  mountain  (Acer spicatum  Lam.). 

Mespilus  cuneata  Miq.,  Japan. 

Mo  alustris  Lit 

Mountain  ash  (Sorbus  americana  Marsh). 

Mountain   ash,    European   (Sorbus  aucu- 
paria  Linn.  1. 

Myrtle  (  Myrtus  sp.  1,  Egypt. 

Nectarine  1  /'r</<  ■    sp 

New    Jersey    tea    (Ceanothus   americanus 
Linn  I. 

<  >nk  (Querciis  pedunculata  Ehrh.  .  (Quer- 
elas Bpp.  1,  <  lermany. 

Orchid. 

isandra  terminalis  Sieb.  iV  Zu 
1  Prunus  persica  Sieb.  >v  Zucc). 
i  commun  ■  1  I  ,inn.  1. 

Pear.   Siekle. 


Peony  (Pxonia  sp.). 

Peppergrass      (Lepidium      suffruticosum 

Linn.,  Cav.),  France. 
Planer  a  keakei  C.  Koch. 
Plum  (Primus  domestica  Linn.). 
Poplar,    Lombardy   (Populus  nigra   var. 

italica  Du  Roi). 
Poplar,  white  (Populus  alba  Linn.). 
Quince  (Cydonia  vulgaris  Pers.). 
Raspberry  (Rubus  idxus  Linn.). 
Rose  (Rosa  rugosa  Thunb.). 
Sassafras  (Sassafras  sassafras  Karst.). 
Silverberry  (Elxagnus  argentea  Pursh.). 
Spirxa  spp. 

Spruce  (Abies  firma  Sieb.  &  Zucc). 
Sycamore  (Platanus  sp.). 
Tallow  tree  (Sapium  sebiferum  Roxb.). 


Tamarisk  (Tamarix  afrirana  Poir.). 

Tree    of    Heaven    (Ailanthus   glandulosa 

Desf.). 
Tulip-tree  (Liriodendron  tulipifera  Linn.). 
Umbrella  tree  (Magnolia  tripetala  Linn.;. 
Viburnum  sp. 
Virginia  creeper  (Ampelopsis  quinquffolia 

Michx.). 
Willow,  goat  (Salix  caprea  Linn.). 
Willow,     Napoleon     (Salix     babylonica 

Linn.). 
Willow,  osier  (Salix  viminalis  Linn.). 
Willow,  (Salix  xgyptiaca  Forsk.). 
Willow,  (Salix  pedicellata  Desf.). 
Walnut,  English  (Juglans  regia  Linn.). 
Walnut  (Juglans  sp.). 
Yucca  (  Yucca  sp.  i. 


Algeria. 


PARASITIC    AND    PREDACEOUS    ENEMIES. 

Minute  parasitic  Ilymenoptera  are  often  efficient  enemies  of  this 
scale,  and  in  some  localities  they  apparently  hold  the  insect  in  check. 
If  these  little  friends  are  present,  small  round  holes  can  be  seen  on  the 
dorsal  part  of  the  scale  showing  where  the  adult  escaped.  Those 
more  commonly  found  are  Aphelinus  mytilaspidis  Le  B.,  A.  abnormis 
How.,  A.  fuscipennis  How.,  A.  diaspidis  How.,  Aspidiotij^agus 
cilrinus  How.,  Anaphes  gracilis  How.,  and  Cheiloneurus  diaspidinanim 
How. 

The  larvoR  of  coccinellids,  or  ladybeetles,  are  sometimes  found  feed- 
ing on  these  insects,  and  certain  species  of  mites  assist  in  their  de- 
struction. Birds  are  also  credited  with  doing  service,  the  most  elli- 
cienl  being  the  titmice  and  tree  creepers. 

THE   SCURFY  SCALE. 

( 'hionaspis  furfura  Fitch,  i 

The  scurfy  scale,  while  infesting  a  considerable  number  of  plants, 
is  a  less  general  feeder  than  is  the  preceding  species.  It  occurs  prin- 
cipally upon  rosaceous  plants,  such  as  the  apple,  peach,  pear,  plum, 
cherry,  etc.,  and  also  on  currant  and  gooseberry  among  cultivated 
plants,  hut  seldom  becomes  so  abundant  as  to  cause  particular  in- 
jni\  or  to  require  spec  die  treatment.  The  insect  may  be  recognized 
from  the  accompanying  illustration  (fig.  2),  much  enlarged.  The 
scale  of  the  female  is  dirty  gray  in  color,  irregularly  pear-shaped,  as 
shown  in  the  picture.  The  male  scales  are  much  smaller,  elongate, 
snow\  white,  with  three  distinct  keels  extending  longitudinally 
along  the  back.  Unlike  the  former  species,  the  scurfy  scale  is  a 
native  North  American  insect,  and  appears  to  be  less  adaptable  to 

[Clr.  iui  I 


the  various  conditions  throughout  the  country.and  has  thus  a  more 
restricted  distribution. 


LIFE     IIISTOKY     AND     IIAIU'IS. 


The  scurfy  scale,   like  the  oyster-shell  scale,   winters  in   the  egg 
condition  under  the  scales.     The  number  which  may  be  deposited 


Fio.  2.— The  scurfy  scale  (Chionaspis  furfura).    Male  at  right,  female  at  left.     Ml  enlarged.      Original.) 

by  a  given  female,  as  may  be  easily  verified  by  examination,  varies 
considerably.  The  following  records  show  the  number  of  eggs  from 
each  of  twenty  individuals: 

Number  of  eggs  deposited  by  the  scurfy  scale,     |  Material  collected  on  applt  sprouts  from 
bas<  of  applt  si, imp  MarchSl,  1905,  at  Arlington  Farm,   Virginia.) 


Scale 

Eggs. 

No 

No 

No 

Eggs. 

1 

61 

6 

71 

11 

54 

10 

2 

18 

7 

78 

12 

111 

17 

Zi 

3 

78 

B 

7il 

13 

1- 

Is 

83 

l 

18 

9 

19 

14 

• 

19 

21 

■  i 

in 

•11 

15 

7» 

20 

33 

\v  til'.-  niiinl>er  of  eggs  per  scale,  57.5. 
36826— (ir.  Ul— 10 2 


The  following  records  from  literature  and  from  the  Bureau  of 
Entomology  will  indicate  the  times  of  hatching  of  the  eggs  of  this 
insect  in  the  spring  for  several  localities: 

Ontario:  Eggs  hatch  about  June  1  (Jarvis). 

Connecticut:  Eggs  hatch  usually  between  May  20  and  June  1  (Britton). 

New   York:  Eggs  hatch  at  about  same  time  as  those  of  oyster-shell  scale. 

Ohio:  Eggs  hatch,  and  young  arc  crawling,  during  latter  part  of  May  or  in  early  June 
(Houser). 

Illinois:  Eggs  hatch  from  June  5  to  12  (Walsh). 

Missouri:  Eggs  hatch  soon  after  the  formation  of  the  young  apples,  the  date  depend- 
ing upon  locality  and  upon  forwardness  of  the  spring  (Taylor). 

District  of  Columbia:  Eggs  hatch  from  May  15  to  June  1  (Howard). 

Delaware:  Eggs  hatch  about  same  time  as  those  of  oyster-shell  scale,  which  is  usually 
early  in  May  (Houghton). 

Tennessee:  Eggs  hatch  in  April,  and  there  are  two  broods  annually  (Bentley). 

Georgia:  In  1906  eggs  hatched  March  11  to  22.  Eggs  for  second  brood  hatched 
beginning  about  June  2. 

In  the  more  northern  States  there  is  but  one  brood  each  year,  but 
in  the  South,  as  in  Tennessee  and  in  Georgia,  there  are  evidently 
two  full  broods,  and  in  the  latter  State  there  is  a  strong  probability 
of  a  third.  Thus,  at  Myrtle,  Ga.,  in  1906,  the  eggs  were  hatching 
March  11,  and  hatching  had  probably  ceased  by  March  22.  Males 
of  the  new  brood  appeared  May  15,  and  eggs  had  been  deposited  by 
the  female  May  28,  the  hatching  beginning  June  2. 

DISTRIBUTION. 

The  following  records  of  distribution  have  been  compiled  from 
various  publications  and  from  data  collected  by  the  Bureau  of 
Entomology : 

California,  Colorado,  Connecticut,  Delaware,  District  of  Columbia, 
Georgia,  Idaho,  Illinois,  Indiana,  Iowa,  Kansas,  Kentucky,  Maine, 
Maryland,  Massachusetts,  Michigan,  Minnesota,  Missouri,  Nebraska. 
New  Hampshire,  New  Jersey,  New  York,  North  Carolina,  Ohio, 
Pennsylvania,  Rhode  Island,  South  Carolina,  South  Dakota,  Ten- 
nessee, Utah,  Virginia,  Washington,  Wesl  Virginia,  and  Wisconsin. 
In  Canada  it  is  recorded  from  New  Brunswick,  Nova  Scotia,  Ontario, 
and   Prince   Edward    Island. 

FOOD    PLANTS. 

The  following  list  includes  all  plants  upon  which   this  species  has 
been  found,  so  far  as  it  has  been  possible  to  determine  from  records 
in  literature  and  from  those  in  the  Bureau  of  Entomolpgy: 
[Cir.  121 J 


Apple  (Pyrus  mains  Linn.). 

Apple,  Chinese  flowering  (Pyrus  specta 

Lit.). 
Apple,  crab  i  Pyrus  sp.). 
\-l*     European  mountain  (Sorbus 

pwria  Linn 
Ash,  mountain  (Sorbus  americana  Ail 
Ash,    prickly    (Xanthoxylon   americanum 

Mill 
Ash,  while  i  Fraxinus americana  Linn.). 
Aspen,  largetooth  (Populus  grandia 

Michx.). 
Buckthorn  (Rhamnus  cathartica  Linn. 
Cherry,  choke  (Prunus  virginiana  Linn.). 
Cherry,     wild     black     [Prunus    serotina 

Ehrh 
Cherry,  wild  red  <l'mn>is  pennsylvanica 

Linn.). 
Chokeberrj  (Pyrus Jloribunda  Lindl.). 


Elm  (  Ulmus  sp.). 

Goo  i  ben  \  i  Ribes  sp 

Hawthorn  ((  ratxgus  oxyacantha  Linn.). 

Hickory,  big  bud  i  Hieoria  alba  Britl 

Hoi  e  chestnul  (JSsculus   hippo 

Linn  i. 
Peach  il'niniiH  persica  Sieb.  *V  Zucc 
Pea]  ■  a in, lis  Linn  i,  (P.  ft<  /</•<<- 

phijlla  Pur. ). 
Plum  ( /'mints  pissardii  Horl 
Plum,  common  garden  (Prunus  domeslica 

Linn. ). 
Quince  (Cydonia  vulgaris  Per 
Quince,  Jap  sPei 

Raspberry,  black  cap  I  Halms  occidentalis 

Pei 
Red  iv.  igged  do  wood  (doubtful  r< 
Shad-bush       I  canadensis    Me 

die). 


Chokeberry,    black   (Sor&us   melanocarpa  Sweet  gum  (Liquidambar    p 

C.  Koch  Sweet     pepper    bush     (Clethra    alni/olia 

Chokeberry,    red    (5orfeiM   arbulifolia   C.  Linn 

Koch)  Walnut,  black  (Juglans  nigra  Linn.). 

"Cherrj  currant."  Willow,  white  (Salix alba  Linn.). 

Currant,  red  flowered  (Ribes  sanguineum 
Pursh.  i.  England. 

Tin  scurfy  scale  is  especially  common  on  apple  and  pear,  less  usu- 
ally so  on  cherry  and  peach,  on  winch  latter  hosi  in  the  South,  in  cer- 
tain cases  which  have  come  under  the  writers'  obsen  ations,  it  proved 
\ei'\  destructive,  greatrj  stunting  the  trees,  although  none  had  actu- 
ally been  killed. 


PARASITIC     VST)    PREDACEOUS    ENEMIES. 

This  species  is  apparently  not  so  subject  to  attack  of  parasitic  and 
predaceous  insects  as  the  preceding,  or  else  attention  has  not  been 
directed  to  this  phase  of  the  insect's  economy  to  an  equal  extent. 
The  following  predaceous  species  are  recorded  as  feeding  upon  the 
scurfy  scale:  Tyroglyphus  malus (Shimer),  Chilocorus  bivulnerus  Muls., 
and  Hypi  raspidis  sp. 

^mong  the  parasitic  Hymenoptera,  Ablerus  clisiocampa.  (Ashm.) 
has  keen  reared  from  this  species,  as  well  as  Physcus  varicornis  I  low.. 
and  a  species  of  the  genus  ProspalU  lla. 

METHODS  OF  CONTROL  FOR  BOTH  SPECIES. 

Preparatory  to  spraying  orchard,  shade,  and  ornamental  trees  and 
plants  for  scale  insects,  they  should  be  carefully  gone  over  and  any 
dead  and  weakened  parts  primed  out.  The  presence  of  such  dead 
and  dying  wood  is  a  distinct  detriment,  and  its  removal  will  greatlj 
simplify  t he  work  of  spraying. 

[Clr.  121  I 


10 

TREATMENT    OF    ORCHARDS. 

In  orchards  well  sprayed  during  the  dormant  period  for  the  San 
Jose  scale  each  year,  the  oyster-shell  and  scurfy  scales  will  rarely 
prove  troublesome.  While  these  insects,  by  reason  of  wintering  in 
the  egg  stage  under  the  protecting  female  scales,  are  less  susceptible 
to  washes  effective  against  the  San  Jose  scale,  yet  the  treatments 
will  in  most  cases  keep  them  reduced  below  injurious  numbers. 

In  orchards  where  spraying  for  the  San  Jose  scale  is  unnecessary  and 
where  the  oyster-shell  or  scurfy  scales  are  troublesome,  specific  treat- 
ments become  necessary.  There  is  considerable  difference  of  opinion 
among  entomologists  as  to  the  effectiveness  of  sprays  applied  during 
the  dormant  season  to  effect  the  destruction  of  the  eggs,  but  there  is 
greater  uniformity  as  to  the  effectiveness  of  spraying  shortly  after 
the  young  have  hatched  and  before  there  has  been  time  for  the  forma- 
tion of  a  thick  protecting  scale. 

Tims  Messrs.  Parrott,  Beach,  and  Sirrine,0  referring  to  the  scurfy 
scale,  state: 

During  the  work  of  the  past  two  years  opportunities  have  been  given  to  note 
the  effects  of  the  sulphur  washes  upon  this  species.  In  several  instances  where  the 
infestation  was  moderate,  such  treatment  has  usually  checked  the  further  develop- 
ment of  the  scales.  When  the  incrustation  was  heavy,  the  results  attending  the 
application  of  the  washes  have  shown  some  variation  in  the  amount  of  reduction  of 
the  scales,  but  there  has  usually  been  a  very  appreciable  destruction  of  the  insects. 

Writing  of  the  oyster-shell  scale,  Mr.  William  Stuart  says:6 

Early  spring  applications  do  not  appear  to  be  a  practicable  method  of  eradicating 
the  oyster-shell  scale.  Summer  treatment  of  infested  trees,  soon  after  the  young 
have  hatched,  with  dilute  kerosene  emulsion,  whale-oil  soap,  or  tobacco  infusions 
affords  a  much  more  effective  means  of  combating  this  pest. 

Experiments  were  made  by  Mr.  Stuart  in  the  use  of  the  cooked 
lime-sulphur  wash  in  1904,  and  the  kerosene-limoid  mixture  in  1905. 
In  1906  tests  were  made  of  the  cooked  lime-sulphur  sprays.  All 
applications  were  made  during  the  dormant  period  of  the  trees. 

The  Rev.  Chas.  J.  S.  Bethune  states :c 

Owing  to  the  large  number  of  applicants  who  were  desirous  of  obtaining  information 
on  the  best  methods  of  combating  the  oyster-shell  bark  louse,  it  was  decided  to  carry 
on  a  number  of  experiments  here,  to  test  the  efficiency  of  the  '"arious  insecticides 
commonly  used  against  scale  insects. 

Of  all  the  spray  mixtures  tried,  the  well-known  lime,  salt,  and  sulphur  wash  gave 
the  best  results. 

Tho  lime,  sulphur,  and  caustic  soda,  and  the  lime,  sulphur,  and  sal  soda  were  also 
tried,  but  without  quite  such  good  results.  The  lime,  sulphur,  and  caustic  soda 
proved  to  be  a  little  superior  to  the  lime-sulphur  and  sal  soda,  owing  to  its  apparent 
power  of  better  penetration. 

a  Bui.  262,  N.  Y.  Agr.  Exp.  Sta.  (Geneva),  1905. 
b  19th  Ann.  Rep.,  Vermont  Agr.  Exp.  Sta.,  p.  294,  1907. 
c32d  Ann.  Rep.  Ont.  Agr.  Coll.  and  Exp.  Farm,  p.  48,  1906. 
[Cir.  121] 


11 

Soaps. — Various  Boape  were  also  tried,  and  of  these  the  whale-oil-soap  emulsion 
gave  the  beBl  results,  many  of  the  Bcales  being  killed.     The  whale-oil  Boap  gave  - 
results  also,  bul  qoI  equal  to  the  emulsion 

Keroseru  emulsion      Kerosene  emulsion  was  also  and  this  proved  of  more 

value  than  the  whale-oil-soap  emulsion,  but  doI  so  effective  as  the  lime,  salt,  and 
sulphur  wash. 

Lime. — Quick  slaked  lime,  \\  pounds  to  I  gallon  of  water,  proved  very  effective 
applied  as  a  winter  wash,  and  equaled  the  results  obtained  by  the  Hum',  Bait,  and 
sulphur. 

A',  ton  in  lime.  This  was  also  tried,  but  did  not  prove  superior  to  the  kerosene  emul- 
sion, and  therefore  is  QOl  to  lie  preferred  to  it. 

Prof.  T.  B.  S\  mi.  > t i ^ ,  as  a  resull  of  tests  of  sprays  upon  the  oyster- 
shell  scale  on  shade  trees  in  1906,  concludes: 

That  maple  tiers  infested  with  the  oyster-shell  scale  can  be  treated  both  in  the  fall 
and   early   Bpring   with    the   line-sulphur  and   salt    wash    with  satisfactory   result 
regards  controlling  the  pest,  and  without  injury  to  the  trees. 

That  where  one  application  is  made  these  tests  showed  the  fall  treatment  to  be 
preferable.  It  is  the  writer's  belief,  however,  thai  when  the  wash  is  applied  thoroughly 
in  early  spring  equally  good  or  even  better  results  can  1 btained. 

The  Duke  of  Bedford  and  Spencer  V.  Pickering6  report  results 
of  detailed  experiments  with  various  washes  in  the  destruction  of 
the  eggs  of  this  insect,  and  found  thai  a  •'!  per  cent  caustic  soda  wash 
gave  100  per  cent  efficiency  in  killing  the  eggs.  A  2.5  per  cenl 
caustic  soda  wash  with  soap  also  gave  excellenl  results,  but  diffi- 
culty was  experienced  in  handling  the  wash  on  accounl  of  its  becom- 
ing semisolid.  Results  of  tests  of  other  washes  are  presented,  as 
caustic  soda  and  potash,  paraffin  emulsion,  emulsion  soda  washes, 
emulsions  with  lime,  lime-sulphur  soda  washes,  etc. 

Concerning  the  scurf}  scale,  Mr.  J.  S.  Houser'  state-. 

That  the  lime-sulphur  wash  applied  during  the  winter  is  effecth  e,  as  are  also  c  in- 
tact sprays  applied  at  hatching  time. 

The  same  ant  I  tor  (1  c),  in  speaking  of  the  oyster-shell  scale,  states: 

The  lime-sulphur  wash  is  undoubtedly  the  control  method  to  be  used  against  this 
scale,  but  in  the  author'-  experience,  it  has  proven  somewhat  of  a  disappointment. 
From  observations  made  upon  hundreds  of  trees  and  shrubs,  sprayed  with  a  mixture 
made  b)  experienced  men  and  applied  thoroughly,  it  is  apparent  that  only  when  con- 
ditions are  the  most  favorable  are  the  results  following  its  use  satisfactory.  A  slight 
dampness,  such  as  i  at  the  time  of  application,  a  somewhat  weakened  spraying 

mixture,  an  extra  case  of  infestation,  where  several  scales  are  piled  upon  one  another, 
a  temperature  below  ;:  i       of  these  unfavorable  conditions  is  sufficient  to 

gh  e   | 

Prof.  K.  A.  Coolev  '  presents  results  of  extensive  tests  of  sprays  for 
the  destruction  of  the  ovster-shell  scale:  (1 1  As  againsl  th  inr- 


<<  Bul.  Ill,  Md.  Agr.  Exp.  Sta., 

>■  8th  Rep.  Woburn  Exp.  Fruit  Farm,  p.  33,  1908. 

Bul.  194,  Ohio  Agr.  Exp.  Sta  .  1908. 
dJoura    I      m.  I'.nt.,  vol,  3,  p.  57,  MHO. 
[Clr.  121] 


12 

ing  dormant  period  of  trees;  (2)  early  during  hatching  period  of  eggs, 
and  (3)  late  during  hatching  period  of  eggs.  The  results  were  not 
entirely  consistent,  and  further  experiments  are  promised.  The  two 
following  points,  however,  are  emphasized: 

(A)  Eggs  of  the  oyster-shell  scale  are  unaffected  by  the  application  of  lime-sulphur 
solutions  made  previous  to  the  opening  of  the  buds.  On  trees  so  sprayed  the  young 
were  killed  very  soon  after  hatching.  The  intervention  of  rain  storms  before  the  hatch- 
ing of  the  eggs  may  more  or  less  affect  the  value  of  the  treatment. 

(B)  It  is  indicated  that  emulsions  of  linseed  oil  and  cottonseed  oil  may  be  useful  for 
the  treatment  of  this  insect  while  in  the  egg  stage  and  during  the  hatching  period. 

On  the  whole,  therefore,  it  would  appear  preferable,  where  the  de- 
struction of  these  insects  alone,  is  to  be  considered ,  to  spray  as  the  young 
insects  are  hatching  in  the  spring.  The  table  of  dates  of  hatching 
given  under  the  remarks  on  life  history  for  each  species  will  indicate 
approximately  when  the  young  insects  may  be  expected  to  appear, 
but  this  time  may  be  accurately  determined  by  frequent  examina- 
tions of  the  infested  trees.  The  very  small,  yellow  insects  will  be 
seen  in  numbers  crawling  over  the  limbs  and  branches  in  their  efforts 
to  find  a  suitable  place  for  settling. 

The  data  on  the  dates  of  hatching  of  the  two  species,  considered 
in  connection  with  blooming  dates  of  fruit  trees,  indicate  that  for  any 
locality  the  young  of  both  species  will  have  hatched  and  settled,  and 
may  be  effectively  treated  during  the  period  of  from  one  to  three 
weeks  following  the  blooming  period  of  the  apple;  and  from  two  to 
four  weeks  after  the  period  of  blooming  of  the  peach.  It  will  be 
preferable,  however,  positively  to  determine  the  time  of  crawling 
of  the  young  for  the  particular  locality  and  food  plant,  by  actual 
observations. 

In  spraying  for  the  young  insects  when  the  trees  are  in  foliage,  the 
presence  of  the  leaves  will  render  thorough  work  more  difficult,  and 
especial  care  will  be  necessary  to  reach  all  limbs  and  branches,  treat- 
ing every  portion  of  the  tree  from  top  to  bottom,  as  only  those  insects 
actually  hit  are  destroyed.  A  weaker  wash  must  also  be  employed 
than  during  the  dormant  season,  as  will  be  indicated  later  under  the 
head  of  formulas,  or  else  injury  to  the  foliage  and  fruit  may  result. 

TREATMENT  OF  SHADE  TREES. 

The  oyster-shell  scale  will  often  require  treatment  on  maples, 
Lombard  y  and  Carolina  poplars,  ash,  and  willow.  As  these  trees 
will  be  rarely  sprayed  during  the  dormant  period  for  other  scale  pests, 
it  will  be  advisable  to  give  the  treatment  just  after  the  hatching  of 
the  young,  as  already  explained.  Effective  spraying  of  shade  trees, 
when  these  are  of  some,  size,  will  require  painstaking  work.  In  many 
cases  it  will  he  necessary  for  the  man  handling  the  nozzle  to  climb 

[Cir.  121] 


into  the  trees  to  reach  the  higher  liml>s  and  branches  and  a  long  exten- 
sion or  bamboo  rod  is  indispensable.  The  Length  of  hose  must  be 
adapted  to  the  height  of  the  trees  to  be  treated,  and  a  coarse  nozzle, 
such  as  the  Bordeaux,  will  he  preferable,  as  enabling  the  operator  to 
throvi  the  spray  some  distance  to  inaccessible  branches.  A  high- 
pressure  pump,  from  1"><>  to  200  pounds,  is  especially  desirable, 
though  the  writers  have  seen  Lr"od  work  accomplished  with  an  ordi- 
nary barrel  out  lit. 

Spraying  during  the  dormant  season,  however,  may  be  practiced, 
if  the  work  may  he  more  conveniently  accomplished  during  this 
time,  using  one  of  t  he  winter  sprays  later  mentioned .  as  lime  sulphur 
wash,  kerosene  or  crude  petroleum  emulsion  i_'ii  to  25  per  cent 
strength),  or  some  of  the  miscible  oils. 

TREATMENT     OF     CURRANTS,     GOOSEBERRIES,     ORNAMENTAL     SHRUBS, 
WlHiniKi:  LOW-GROWING  PLANTS. 

After  proper  pruning,  shrubs  and  hushes  infested  with  these  two 
scale  pests  should  he  thoroughly  sprayed,  preferably  as  the  young 
are  hatching  in  the  spring,  using  the  summer-strength  kerosene  or 
crude-petroleum  emulsion  or  whale-oil  soap  wash.  A  knapsack  or 
bucket  pump  will  he  suitable  for  treating  a  few  plants  in  yards,  and 
in  view  of  the  small  amount  of  labor  involved,  a  supplementary 
application  is  advisable  in  a  week  or  ten  days  to  destroy  any  belated 
larvae  which  escaped  the  first  application.  Where  infested  yard 
plants  are  growing  close  t,>  the  wall  of  a  building,  this  may  he  pro- 
tected during  the  operation  of  spraying  by  a  piece  of  tarpaulin  or 
other  heavy  cloth,  or  even  refuse  paper. 

SPRAY  FORMULAS. 

Kerosem  emulsion  (stock  solution,  66  />< r  cent  <>il). — Kerosene 
emulsion    is    made   after   the   following  formula: 

Cer -1  oil,  lamp  oil) gallons. .     2 

Whale-oil  or  laundry  soap  (or  I  quart  soft  soap) pound..     ^ 

Water gallon. .     1 

The  snap  should  first  be  dissolved  in  boiling  water;  then  remove 
vessel  from  the  lire.  Immediately  add  the  kerosene,  and  thoroughly 
agitate  the  mixture  until  a  creanrj  solution  results.  The  stock 
emulsion  max  be  more  conveniently  made  by  pouring  the  mixture 
into  the  tank  of  a  spray  pump,  and  pumping  the  liquid  through  the 
nozzle  hack  into  the  tank  fur  some  minutes.  The  stock  solution, 
if  well    made,   will    keep    for   SOme    months,   and    is   to   he   diluted    hei'me 

using.     In  order  to  make  a  lu  per  cent  spraj   'the  strength  (<<v  trees 

in    foliage)    add     to    each     1     gallon    of    the    stock    solution     about      5 

LT.-ilh >n^  of  water,     for  20  and  _'■">  p<  r  cent  emulsions  (for  use  on  dor- 

[Clr.  121] 


14 

infant  trees  and  plants)  use  respectively  about  2\  and  1§  gallons 
of  water  for  each  1  gallon  of  stock  emulsion.  Agitate  the  mixture 
in  all  cases,  after  adding  the  water.  The  preparation  of  the  emul- 
sion will  be  simplified  by  the  use  of  a  naphtha  soap.  No  heat  will 
be  required,  as  the  kerosene  will  combine  readily  with  the  naphtha 
soap,  in  water,  when  thoroughly  agitated.  Double  the  quantity  of 
naphtha  soap  given  in  the  above  formula,  however,  will  be  required, 
and  soft  or  rain  water  should  be  used  in  making  the  emulsion.  In 
regions  where  the  water  is  "hard,"  this  should  first  be  broken  with 
a  little  caustic  potash  or  soda,  as  common  lye,  before  use  for  dilution, 
to  prevent  the  soap  from  combining  with  the  lime  or  magnesia  present, 
thus  liberating  some  of  the  kerosene,  or  rain  water  may  be  employed. 

Crude  petroleum  emulsion. — Crude  petroleum  emulsion  may  be 
prepared  in  identically  the  same  way  as  described  for  kerosene 
emulsion,  substituting  crude  petroleum  for  kerosene.  The  grade  of 
crude  petroleum  employed  in  the  East  is  that  known  as  "insecticide 
oil,"  having  a  specific  gravity  of  43°  to  45°  Baume.  The  same 
dilutions  for  winter  and  summer  spraying  should  be  observed  as 
stated  for  kerosene  emulsion,  but  it  should  be  noted  that  for  summer 
treatments  of  trees  in  foliage  the  kerosene  emulsion  is  preferable, 
as  it  is  less  likely  to  cause  injury. 

Whale-oil  soap  wash. — There  are  several  brands  of  whale-oil  soap 
on  the  market.  Potash  soap  is  preferable,  and  it  should  not  contain 
over  30  per  cent  of  water.  For  spraying  dormant  trees  the  soap  is 
dissolved  in  hot  water  at  the  rate  of  2  pounds  to  each  1  gallon,  and 
spraying  should  be  done  before  the  wash  cools,  otherwise  it  is  forced 
through  the  nozzle  with  difficulty.  For  spraying  trees  in  foliage 
use  the  soap  at  the  rate  of  1  pound  to  3  or  4  gallons  of  water,  or  even 
weaker. 

Lime-sulphur  wash. — Lime-sulphur  has  become  the  main  reliance 
in  spraying  orchards  infested  with  the  San  Jose  scale,  and  is  effective 
in  controlling  numerous  other  insects  and  is  valuable  for  certain 
fungous  troubles.  The  following  formula  is  used  only  on  dormant 
t  rees : 

Stone  lime pounds. .   20 

Sulphur  ( flour  or  flowers) do 15 

Water  id  make gallons. .   50 

Heat  in  a  cooking  barrel  or  vessel  about  one-third  of  the  total 
quantity  of  water  required.  When  the  water  is  hot  add  all  the  lime 
and  at  once  add  all  the  sulphur,  which  previously  should  have  been 
made  into  a  thick  paste  with  water.  After  the  lime  has  slaked, 
about  another  third  of  the  water  should  be  added,  preferably  hot, 
and  the  cooking  should  be  continued  for  an  hour,  when  the  final 
dilution  may  be  made,  using  either  hot  or  cold  water,  as  is  most  con- 

[Cir,  123  I 


venient.  The  boiling  due  to  the  slaking  of  the  lime  thoroughly 
mixes  the  ingredients  at  the  start,  but  subsequent  stirring  is  acces- 
sary if  the  wash  is  cooked  In  direcl  heal  in  kettles,  [f  cooked  \>\ 
steam  no  stirring  will  be  uecessary.  After  the  wash  has  been  pre- 
pared it  must  be  well  strained  as  it  is  being  run  into  the  spray  pump 
or  tank.  The  wash  may  be  cooked  in  large  kettles  or  preferably  l>\ 
steam  in  barrels  or  tanks. 

Miscibh  oils. — Under  the  head  of  miscible  oils  are  designated 
several  commercial  insecticides  coming  into  considerable  use  as  spraj  s 
for  scale  insects  during  the  dormant  period  of  the  trees,  and  their 
use  will  often  be  advantageous,  especially  where  but  a  few  tree-  are 
to  be  treated.  Miscible  oils  should  be  used  on  dormant  tree-  at  the 
strength  recommended  by  the  manufacturers. 

Commercial  limesulpkw  washes.  There  are  on  the  market  several 
brands  of  concentrated  lime-sulphur  solutions,  designed  to  replace 
the  homemade  lime-sulphur  wash,  mentioned  above.  These  washes 
in  general  have  proved  to  be  satisfactory  for  the  control  of  the  San 
Jose  scale,  and  will  doubtless  be  about  as  effective  against  the  oyster- 
shell  and  scurfj  scales  as  the  homemade  wash,  the  preparation  of 
which  may  thus  be  avoided  if  desired.  These  may  be  used  on  dor- 
mant trees,  or,  much  more  dilute,  on  trees  in  foliage. 

Approved: 

J  IMES    Wn  SON, 

Si  cri  tary  oj  .  igriculiurt . 
Washington,  D.  ('..  March  30,  Wlu. 

[Cir.  121] 

o 


UNIVERSITY  OF  FLORIDA 

llllllilllj 

3  1262  09216  5553 


